The present invention relates to wrenches with enhanced mechanical advantage, provided in combination with other useful features.
Wrenches are well known in the art for a variety of functions. One important kind of wrench is known as an X-wrench, which is typically used by motor vehicle owners. An X-wrench has a square cruciform shape and is used for removing nuts from the hub of a motor vehicle, in order to remove a wheel, typically a wheel with a flat tire. The cruciform X-shape is used so that the tip of each arm of the X may be provided with a socket of different size, so that up to four different socket sizes may be found on an X-wrench. Each socket is welded onto the tip of an arm, so that the socket sizes may not be changed. But, typically, the four socket sizes that are added to an X-wrench are sufficient to be applicable to the nut sizes found on most types of motor vehicle.
On the one hand, the X-wrench has some advantages, namely, multiple socket sizes usually mean that a suitable socket will be found on at least one branch. The cruciform shape allows a user to fit a socket over a wheel nut and exert a force couple to the nut by pulling on one arm of the X-wrench, and pushing on the other. As is known, a force couple does not apply any shear force to the nut, but applies only a pure moment for rotating the nut.
But on the other hand, an X-wrench has some disadvantages. First, the cruciform shape is unwieldy, and requires a large area in an automobile where it may be conveniently stores. Second, the cruciform shape provides the user with two arms for rotating a nut, and each arm is approximately eight inches long. Because there are two arms, a user may apply a bending moment via each arm, and this moment couple typically is sufficient to undo a nut. However, it frequently occurs that a wheel nut becomes stuck fast so that a user with ordinary physical strength cannot develop sufficient moment to undo the nut. In these circumstances, it is tempting for the user insert a socket over the nut, and to stand on one of the arms in order to generate a large counterclockwise moment on the nut. This introduces two problems. First, a large shear force and longitudinal bending moment is introduced into the nut, tending to bend the nut downwards. This may have catastrophic consequences, in that the nut may snap, or, if the nut is mounted on a stub, the stub may snap. Second, the user now has only one half of the moment arm that was available in the couple, namely the approximately eight inches available in a single arm.
Thus, there is a need in the art for a solution to problems encountered in wrenches configured for wheel nut removal. The present invention addresses these and other problems.